You'll also have to deal with global diplomacy. Every member state that helps pay for the XCOM project will ask for your assistance - either dealing with aliens or sending over technology - and you'll have to keep everyone happy to keep the money rolling in.

This iOS edition of XCOM: Enemy Unknown is almost an exact port of the console and PC game.

Multiplayer won't be available at launch, but will be added in the future. Plus, as XCOM: Enemy Unknown lead designer Jake Solomon explains, making it fit on iOS meant "down-rezzing" the textures and "cutting the map count... quite a bit".

But XCOM: Enemy Unknown for iOS won't have any in-app purchases, so the game's ruthless, my-best-sniper-just-got-bumrushed-by-a-Muton difficulty will be just as you left it.

XCOM: Enemy Unknown will go live on the App Store on Thursday. It will work on the iPad 2, third-gen iPad, iPad with Retina display (iPad 4), iPad mini, iPhone 4S, iPhone 5, and fifth-gen iPod touch.

There will also be Game Center integration for achievements and iCloud support for save syncs.

We're going to post loads of content on the game throughout the week, including a review, some handy tips, some videos, and more.